Question

What is the PAR range?
A) 200 nm - 800 nm
B) 400 nm - 700 nm
C) 350 nm - 550 nm
D) 100 nm - 600 nm

Answer 1

Hint: PAR stands for Photosynthetically Activation Radiation. This range of solar radiation has been used by photosynthetic organisms. They use this radiation in the process of photosynthesis. The photosynthesis can be carried out by specific species such as plants, some bacteria such as cyanobacteria, and heliobacteria.

Complete answer:
Let's study more about PAR. It's a spectral range of solar radiation that is being used by organisms who produce food. This waveband almost corresponds with the waveband of light (able to see by the naked eye). Photos with shorter wavelengths have high energy which can damage DNA by deletion and can also interfere with metabolic activity. But they get filtered out by the ozone layer. Also, on the other hand, photons with higher wavelengths do not have enough energy to carry out photosynthesis.
As we know that chlorophyll is abundant in plant leaf cells and has carotenes and xanthophylls pigments that can absorb green light and initiate the process of photosynthesis. Since this PAR range almost corresponds with the light wave band, it has a range of 400 nm to 700 nm. PAR measurement is used in agriculture, forestry, and oceanography. PAR can be used to evaluate agricultural investment potential.

So the correct answer is B, 400 nm - 700 nm.

Note: Some living organisms such as cyanobacteria, purple bacteria, and heliobacteria absorb photons from the near-infrared spectrum. These bacteria live in a deep-sea or at the bottom of the ponds and they reflect a green, purple, and red color. And these bacteria produce food on their own.